Sadiq Khan has written to Home Secretary Sajid Javid, urging him to ban the political wing of Hezbollah ahead of this weekend's Al Quds Day parade where people wave the group's flag.
The London Mayor has urged Mr Javid to close a legal loophole that means people can fly the terror group's flag on so-called "political grounds", because Hezbollah's military wing is proscribed as a terrorist group in Britain but its political wing is not.
Last year, the Hezbollah flag, which depicts an AK-47 assault rifle, was a common sight at the annual Al Quds Day parade in London. The next parade is on Sunday.
The mayor's spokesperson told the JC: “Anti-Semitism or hate crime of any kind has no place in our city or in our society.
“Sadiq has written to the Home Secretary to raise his deep concerns about the support shown for Hezbollah at the annual Al Quds Day march.
"He has called on him to urgently reconsider his predecessor’s decision not to take action to stop this.”
Mr Khan has earlier said it was “astonishing” that the law continues to allow public displays of support for the Iranian led organisation.
Critics have long argued that there is no distinction between Hezbollah’s political and military wings.
“What is astonishing is there are people using a loophole in the law to fly a flag of an organisation that’s been proscribed – banned, “ said Mr Khan, speaking to another newspaper.
“I know from experience and the letters people write to me and speaking to Londoners that they feel the ripples of hatred. It cannot be right than it 2018 there are Londoners who, by virtue of being Jewish, feel these ripples of hate.”
“What’s happening is people who may feel scared by the flag and the association with what Hezbollah have done will see this flag fly in the heart of our city and think ‘how can that be allowed?’”
Mr Khan previously wrote to the former Home Secretary, Amber Rudd to request she fully proscribe Hezbollah.
The organisation is already banned in the US, Canada and Arab League countries.